You can use a live connection, but uploading the data into a DB might be a better option. Good info at this thread:
Also, a live connection will not have the benefits of some functions like count distinct and median. An extract is required for you to access these functions when using text/Excel/Access files as data sources... most databases would also have the advantage of allowing these functions with a live connection.
More info here:
Do you want to change data sources based on a value in your Excel data (which, itself, is a data source)??
I don't understand what you want to do, can you explain it some more?
He just wants a live connection, I believe. I assume he is asking how to update the data stored in an Excel file.
I assume this because of the sentence: ...so that if I make a change in Excel (to the column containing my variable), the change will automatically be reflected in the visualization in Tableau?
The thread title is a little confusing because of the terms "swap" and "data source".
I have a map visualization that is drawn based on an Excel spreadsheet (say, the values in Column A)... Is there a way to have my visualization change automatically (via a live connection to the data source) via myself manually changing the values in Column A of my spreadsheet?
Yes! Your answer is above. Although with Excel/text files, you still have to "refresh" to get the live data--there is no true live connection to an Excel/text file.
How do I create a "live connection" to an Excel spreadsheet? Would you mind walking me through the process?
"Connect to Data", choose Excel file or Text file for CSV. And you are connected live. Again, you still have to "refresh" to get updated data into Tableau.
So, if you haven't created an Extract, then you ARE connected live. Make a change in your Excel file, then refresh in Tableau to see the change.
Lastly, how do I "refresh" to see the updated changes in my Tableau visualization? And how do I know I haven't created an "extract"?
Click the "Data" menu. If the "Extract Data" option is still active and hasn't been used, you are on a live connection. If I had taken an extract, the Option that says "Extract >" would be active. Similarly, in the data menu, you'll find the "Refresh" option (F5 is the keyboard shortcut)
In this screenshot, I am on a live connection, and the "Extract Data" option is still active and has not been used. You can also see the refresh option.
With an extract, you can schedule updates at regular intervals, and any changes to the Excel file will show up at the time of refresh. Again, I'd prefer to use a database for this, but you can do it with Excel/Text files. Some info here: http://community.tableau.com/thread/124720